add orchestrator

saga/src/main/java/com/iluwatar/saga/orchestration/Chapter.java

@@ -23,13 +23,28 @@
 package com.iluwatar.saga.orchestration;
 
 /**
- * Chapter including into Saga
+ * Chapter is an interface representing a contract for an external service.
+ * @param <K> is type for passing params
  */
 public interface Chapter<K> {
 
+    /**
+     * @return service name.
+     */
     String getName();
 
+    /**
+     * The operation executed in general case.
+     * @param value incoming value
+     * @return result {@link ChapterResult}
+     */
     ChapterResult<K> process(K value);
+
+    /**
+     * The operation executed in rollback case.
+     * @param value incoming value
+     * @return result {@link ChapterResult}
+     */
     ChapterResult<K> rollback(K value);
 
 }

saga/src/main/java/com/iluwatar/saga/orchestration/ChapterResult.java

@@ -1,17 +1,52 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 package com.iluwatar.saga.orchestration;
 
+/**
+ * Executing result for chapter
+ * @param <K> incoming value
+ */
 public class ChapterResult<K> {
-    K value;
-    State state;
+    private K value;
+    private State state;
 
-    public ChapterResult(K value, State state) {
+    public K getValue() {
+        return value;
+    }
+
+    ChapterResult(K value, State state) {
         this.value = value;
         this.state = state;
     }
 
+    public boolean isSuccess(){
+        return state == State.SUCCESS;
+    }
+
     public static <K> ChapterResult<K> success(K val) {
         return new ChapterResult<>(val, State.SUCCESS);
     }
+
     public static <K> ChapterResult<K> failure(K val) {
         return new ChapterResult<>(val, State.FAILURE);
     }

saga/src/main/java/com/iluwatar/saga/orchestration/FlyBookingService.java

@@ -1,5 +1,30 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 package com.iluwatar.saga.orchestration;
 
+/**
+ * Class representing a service to book a fly
+ */
 public class FlyBookingService extends Service<String> {
     @Override
     public String getName() {

saga/src/main/java/com/iluwatar/saga/orchestration/HotelBookingService.java

@@ -1,8 +1,50 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 package com.iluwatar.saga.orchestration;
 
+/**
+ * Class representing a service to book a hotel
+ */
 public class HotelBookingService extends Service<String> {
     @Override
     public String getName() {
         return "booking a Hotel";
     }
+
+
+    @Override
+    public ChapterResult<String> rollback(String value) {
+        if(value.equals("crashed_order")){
+            logger.info("The Rollback for a chapter '{}' has been started. " +
+                            "The data {} has been failed.The saga has been crashed.",
+                    getName(), value);
+
+            return ChapterResult.failure(value);
+        }
+
+        logger.info("The Rollback for a chapter '{}' has been started. The data {} has been rollbacked successfully",
+                getName(), value);
+
+        return super.rollback(value);
+    }
 }

saga/src/main/java/com/iluwatar/saga/orchestration/OrderService.java

@@ -1,5 +1,30 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 package com.iluwatar.saga.orchestration;
 
+/**
+ * Class representing a service to init a new order.
+ */
 public class OrderService extends Service<String> {
     @Override
     public String getName() {

saga/src/main/java/com/iluwatar/saga/orchestration/Saga.java

@@ -25,56 +25,50 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Saga representation.
+ * Saca consists of chapters.
+ * Every Chapter is executed a certain service.
+ */
 public class Saga {
 
     private List<Chapter> chapters;
-    private Result result;
 
     public Saga() {
         this.chapters = new ArrayList<>();
-        this.result = Result.INPROCESS;
     }
 
-    public void setResult(Result result) {
-        this.result = result;
-    }
 
-    public boolean isSuccess(){
-        return result == Result.FINISHED;
-    }
-
-    public boolean isFinished(){
-        return result != Result.INPROCESS;
-    }
 
-    public Saga chapter(String name, int timeoutInSec) {
-        this.chapters.add(new Chapter(name, timeoutInSec));
+    public Saga chapter(String name) {
+        this.chapters.add(new Chapter(name));
         return this;
     }
 
+
     public Chapter get(int idx) {
-        if (chapters.size() < idx || idx < 0) {
-            throw new SagaException("idx shoud be less then ch size or more then 0");
-        }
         return chapters.get(idx);
     }
 
+    public boolean isPresent(int idx) {
+        return idx >= 0 && idx < chapters.size();
+    }
 
 
     public static Saga create() {
         return new Saga();
     }
 
-    public enum Result{
-        FINISHED,CANCELED, INPROCESS;
+    public enum Result {
+        FINISHED, ROLLBACK, CRASHED
     }
-    private static class Chapter {
+
+    public static class Chapter {
         String name;
-        int timeoutInSec;
 
-        public Chapter(String name, int timeoutInSec) {
+        public Chapter(String name) {
             this.name = name;
-            this.timeoutInSec = timeoutInSec;
         }
+
     }
 }

saga/src/main/java/com/iluwatar/saga/orchestration/SagaApplication.java

@@ -24,22 +24,48 @@
 package com.iluwatar.saga.orchestration;
 
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This pattern is used in distributed services to perform a group of operations atomically.
+ * This is an analog of transaction in a database but in terms of microservices architecture this is executed
+ * in a distributed environment
+ *
+ * A saga is a sequence of local transactions in a certain context. If one transaction fails for some reason,
+ * the saga executes compensating transactions(rollbacks) to undo the impact of the preceding transactions.
+ *
+ * In this approach, there is an orchestrator @see {@link SagaOrchestrator} that manages all the transactions and directs
+ * the participant services to execute local transactions based on events.
+ *
+ * @see Saga
+ * @see SagaOrchestrator
+ * @see Service
+ */
 public class SagaApplication {
+    private static final Logger logger = LoggerFactory.getLogger(SagaApplication.class);
+
     public static void main(String[] args) {
+        SagaOrchestrator sagaOrchestrator = new SagaOrchestrator(newSaga(), serviceDiscovery());
 
-    }
+        Saga.Result goodOrder = sagaOrchestrator.execute("god_order");
+        Saga.Result badOrder = sagaOrchestrator.execute("bad_order");
+        Saga.Result crashedOrder = sagaOrchestrator.execute("crashed_order");
 
+        logger.info("orders: goodOrder is {}, badOrder is {},crashedOrder is {}",goodOrder,badOrder,crashedOrder);
+    }
 
 
-    private Saga createSaga() {
-       return Saga.create()
-                .chapter("init an order",10)
-                .chapter("booking a Fly",10)
-                .chapter("booking a Hotel",10)
-                .chapter("withdrawing Money",10);
+    private static Saga newSaga() {
+        return Saga
+                .create()
+                .chapter("init an order")
+                .chapter("booking a Fly")
+                .chapter("booking a Hotel")
+                .chapter("withdrawing Money");
     }
 
-    private static ServiceDiscoveryService sd() {
+    private static ServiceDiscoveryService serviceDiscovery() {
         return
                 new ServiceDiscoveryService()
                         .discover(new OrderService())